This research plan represents the fourth and final stage of research to be conducted by the Environmental Protection Agency's Western Ecology Division (WED) for the Environmental Monitoring and Assessment Program (EMAP) and signals the end of EMAP as a program within EPA's Office of Research and Development. The research proposed will be conducted by members of the EMAP project, primarily housed, but not limited to, the Freshwater Ecology Branch (FEB) at WED. Before presenting the proposed research activities, a review of the history of EMAP and the four phases of its development will set the appropriate stage to evaluate this current research effort.